Nitron analogs containing an N-arylcarbamoylmethyl group and Pd complexes derived therefrom: synthesis and catalytic activity in the Suzuki—Miyaura reaction.

Autor: Chernenko, A. Yu., Baydikova, V. A., Minyaev, M. E., Chernyshev, V. M.
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Zdroj: Russian Chemical Bulletin; Apr2024, Vol. 73 Issue 4, p932-949, 18p
Abstrakt: New 3-arylamino-1,2,4-triazolium salts containing an N-arylcarbamoylmethyl group at the N(1) atom of the 1,2,4-triazole ring were synthesized. They can be used as precursors of N-heterocyclic carbenes (NHCs) capable of coordinating to metals via not only the C(5) atom of the heterocycle but also the atom of the N-carbamoylmethyl group. The selective palladation of the obtained triazolium salts with palladium chloride in pyridine afforded new Pd/NHC complexes, which exhibited enhanced stability against the decomposition accompanied by the Pd—C(NHC) bond cleavage in the presence of strong bases. The enhanced stability of these complexes against bases is attributed to the following two factors: the ionization of the NHC ligand and the formation of chelate complexes. The ionization of the NHC ligand occurs via the deprotonation of the arylamino NH group bound to the triazole ring. The chelate complexes are formed as a result of the deprotonation of the hemilabile N-arylcarbamoylmethyl group and its coordination to the palladium atom giving rise to a Pd—N bond. The synthesized Pd/NHC complexes were found to be highly efficient catalysts for the Suzuki—Miyaura reaction between aryl bromides and arylboronic acids. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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